Who is Superwoman? A Call for Guesses

Supergirl #37
Who is Superwoman?
Last time we talked to Sterling Gates, writer of the Supergirl ongoing series, he was knee-deep in the New Krypton storyline. But he had one tease about what was coming next:

"Start placing your bets on the secret identity of Superwoman. She's not who you think she is."
Beginning with next week's Supergirl #37, the "Who Is
Superwoman?" storyline will be exploring more about the mysterious hero
who showed up in the DCU wearing the familiar S-shaped symbol of the
House of El on her chest. While we've gotten a few hints about her
identity -- she seems to have blue eyes and brown hair, and she speaks
Kryptonian well enough to converse with Kara -- her identity is still a
secret.
Back when we spoke with Geoff Johns about the New Krypton - and Superwoman's debut, he told us about the character: "“I’ll say something about Superwoman - when the idea of ‘New
Krypton’ was floating around James and I knew we wanted to introduce a
mysterious Superwoman. We came up with the idea of who that would be
and why, and some specific beats in New Krypton and beyond, and then
Sterling’s is going to take that and run with it. I just read a scene
in an upcoming issue of Supergirl that he wrote that was...unsettling,”
Johns teased. “I like Superwoman quite a bit and I think came up with
some great plans for her. You need to read Supergirl if you’re not if I
haven’t made that clear.”
Now we're looking for your guesses on who this mysterious caped heroine
could be. After gathering your best guesses on her identity, we'll take
the top 5 guesses and run the names past writer Sterling Gates next
week to get his thoughts on the chances of those characters being the
strange new addition to the Superman universe.
So what do you think? Who is behind that mask? Who is Superwoman?